Master of Engineering Science
Chemical and Biochemical Engineering
Commercialization of Lignin-based phenol formaldehyde resins (LPF) has been limited due to the increase in curing temperatures and decrease in adhesive strength of LPF compared to conventional phenolic resins. Lignin depolymerization can increase the reactivity of lignin; however, the effect of lignin molecular weight on curing performance of LPF resins has yet to be investigated. This research work examined the optimization of synthesis parameters including percent substitution of phenol with lignin, formaldehyde- to-phenol ratio (F/P), and Mw of lignin to reduce the curing temperature and increase the adhesive strength of LPF. DSC analysis indicated that lignin with Mw ~1200g/mol resulted in lowest curing temperature for 75%-LPF while requiring F/P of less than 3. Highest adhesive strength of ~9MPa was attained for 50%-LPF synthesized with F/P of 3 and lignin with high Mw. Incorporation of lignin likely facilitated higher molecular contact and enhanced entanglement; however, it could also increase steric hindrance effects.
Siddiqui, Homaira, "Production of Lignin-Based Phenolic Resins Using De-Polymerized Kraft Lignin and Process Optimization" (2013). Electronic Thesis and Dissertation Repository. 1808.